TABLE 1.

Modulation of Y. enterocolitica infection in BALB/c mice by administration of anti-CD4, anti-CD8, or anti-asialo GM1 Abs and IL-12^a

In vivo modulation treatment		No. of bacteria (log CFU per spleen) on day 7 p.i.	Cytokine level (ng/ml) in:
Ab	IL-12b		HKY-stimulated spleen cells		ConA-stimulated spleen cells
			IFN-γ	IL-4	IFN-γ	IL-4
None (control)	−	6.6 ± 0.2	1.08 ± 0.53	<1.2	6.5 ± 2.2	2.7 ± 0.2
	+	<1.4c	0.43 ± 0.23	<1.2	12.0 ± 7.0	<1.2c
Anti-CD4	−	<1.4c	<0.3c	<1.2	6.2 ± 3.3	<1.2
	+	<1.4	0.43 ± 0.11	<1.2	9.2 ± 4.2	<1.2
Anti-CD8	−	6.6 ± 0.6	0.94 ± 0.09	<1.2	4.8 ± 2.4	2.8 ± 0.4
	+	2.1 ± 0.6c	0.63 ± 0.35	<1.2	10.2 ± 5.1	<1.2c
Anti-NK	−	6.2 ± 0.8	0.52 ± 0.15	<1.2	5.0 ± 7.0	2.1 ± 0.3
	+	3.8 ± 0.6c	1.70 ± 0.9c	<1.2	7.0 ± 3.5	<1.2c

^aMice were infected with 2 × 10³ bacteria and injected with anti-CD4, anti-CD8, or anti-asialo GM1 (NK) Abs on day −1 and +3 p.i. Additional groups of mice were treated with 20 ng of IL-12 on days −1, 0, +1, +2, and +3 p.i. After 7 days, spleens were removed and single-cell suspensions were prepared. One aliquot of this suspension was used to determine bacterial numbers in the spleen, and another part was used to culture 2 × 10⁶ splenocytes per 2 ml of medium with HKY (10 μg per ml) or ConA (3 μg per ml). The supernatants were collected 48 h after stimulation. IFN-γ and IL-4 production were determined by ELISA. Results are the means and standard deviations for four animals. 

^b−, without IL-12; +, with IL-12. 

^cStatistically significantly different from values obtained with control group (P < 0.05).